Hi Steve,
Good question! This is one we have spent a lot of time answering for ourselves, so I will be happy to explain our soil moisture technology.
Most of the soil moisture meters on the consumer market use a simple technology that applies a voltage to two conductive leads in the soil. The current that flows through the soil is proportional to the amount of water the soil holds. We rejected this technology because it is highly affected by saline soils, and the conductive leads can get dirty and lose their calibration very easily.
EasyBloom licenses a special technology for measuring soil moisture from Decagon Devices Inc. It measures the "capacitance" of the soil, which is the ability of the soil to store a non-conductive electrical charge. This technology does not require bare leads exposed to the soil and is not as susceptible to the effects of saline soils.
Percent soil moisture refers to the volumetric percentage of water in the soil at any given time. While soil keeps a constant volume, every soil has pore space that makes up to 35% of the volume of the soil. EasyBloom measures the amount of water held in the pore space as a percentage of the volume of the soil. This is the same technology used to sense soil moisture on the Mars Phoenix Lander!
Thank you for your interest.
Matt
Senior Agricultural Engineer
